Sennheiser RS 220

DSSS, as described by Sennheiser, "is a frequency spreading process in which the output signal is spread to a width of 22 MHz by means of a specified bit sequence." This means that the audio data is transmitted simultaneously on several different frequencies, so if one frequency experiences interference, the data is still able to get through on one or more others. The RS 220 system also doesn't assign an optimum signal volume to its digital data packages. This is a good thing, as it keeps the dynamic range of the music intact - some wireless systems average out the signal, so the quiet sections of a piece end up being louder than intended, and the loud parts quieter.